/* Copyright (C) 2006-2007  Kai Hartmann <kaihartmann@users.sf.net>
 *
 * Contact: cdk-devel@lists.sourceforge.net
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 */

using System.Collections.Generic;

namespace NCDK
{
    /// <summary>
    /// Represents a mapping of two atoms.
    /// </summary>
    // @cdk.module  interfaces
    // @author      kaihartmann
    // @cdk.created 2006-02-15
    public interface IMapping
        : IChemObject
    {
        /// <summary>
        /// Retrieve the first or second of the related <see cref="IChemObject"/>s.
        /// </summary>
        /// <param name="index">The position of the <see cref="IChemObject"/>.</param>
        /// <returns>The <see cref="IChemObject"/> to retrieve.</returns>
        IChemObject this[int index] { get; }

        /// <summary>
        /// Returns an <see cref="IEnumerable{T}"/> to the two <see cref="IChemObject"/>.
        /// </summary>
        /// <returns>An <see cref="IEnumerable{T}"/> to two <see cref="IChemObject"/>s that define the mapping</returns>
        IEnumerable<IChemObject> GetRelatedChemObjects();
    }
}
